var a, b;
function foo(a, b) {
}
foo((x)=>1
, (x)=>""
), foo((x)=>null
, (x)=>""
), foo((x)=>1
, (x)=>null
), foo((x)=>1
, (x)=>1
), foo((x)=>a
, (x)=>b
), foo((x)=>b
, (x)=>a
);
